While developing some XML processing queries, i stumbled on an old bug mentioned in http://wiki.postgresql.org/wiki/Todo#XML: Fix Nested or repeated xpath() that apparently mess up namespaces.
This patch uses function xmlCopyNode that copies a node, including its namespace definitions as required (without unused namespace in the node or its children). When the copy dumped, the resulting XML is complete with its namespaces. Calling xmlCopyNode will need additional memory to execute, but reimplementing its routine to handle namespace definition will introduce much complexity to the code.
